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Abstract:

An integrated energy storage unit includes a container and a battery
housed within the container. The battery includes a positive battery
terminal, a negative battery terminal, and a battery electrolyte. A
capacitor is housed within the container, separate from the battery. The
capacitor includes a positive capacitor terminal, a negative capacitor
terminal, and a capacitor electrolyte. A plurality of connectors
electrically couple the battery and the capacitor in parallel A positive
lead is electrically coupled to the positive battery terminal and the
positive capacitor terminal. The positive lead extends from the
container. A negative lead is electrically coupled to the negative
battery terminal mi{acute over (α)} the negative capacitor
terminal. The negative lead extends from the container.

Claims:

1. A method of assembling an integrated energy storage unit comprising
the steps of: a) manufacturing a battery having a positive battery
terminal and a negative battery terminal; b) manufacturing a capacitor
separate from the battery, the capacitor having a positive capacitor
terminal and a negative capacitor terminal; c) electrically coupling the
positive battery terminal and the positive capacitor terminal to each
other; d) electrically coupling the negative battery terminal and the
negative capacitor terminal to each other; and e) simultaneously charging
the battery and the capacitor from a charge source.

2. The method according to claim 1, further comprising, after step a),
inserting the battery into a battery pouch.

3. The method according to claim 2, further comprising, after step b),
inserting the capacitor into a capacitor pouch.

4. The method according to claim 1, further comprising, after step b),
inserting the battery and the capacitor into a container.

5. The method according to claim 1, further comprising, before step e),
adding an electrolyte to the battery.

6. The method according to claim 1, further comprising, before step e),
adding an electrolyte to the capacitor.

7. A method of assembling an integrated energy storage unit comprising
the steps of: a) inserting positive battery plates and negative battery
plates into a battery pouch; b) inserting positive capacitor plates and
negative capacitor plates into a capacitor pouch; c) electrically
coupling the positive battery plates and the positive capacitor plates to
each other; d) electrically coupling the negative battery plates and the
negative capacitor plates to each other; e) adding a battery electrolyte
to the battery pouch; f) adding a capacitor electrolyte to the capacitor
pouch; and g) simultaneously charging the battery and the capacitor from
a charge source.

8. The method according to claim 7, wherein steps a) and b) comprise
inserting the positive battery plates, the negative battery plates, and
the positive capacitor plates and negative capacitor plates into the same
pouch.

9. The method according to claim 8, wherein the e) and f) comprise adding
the same electrolyte.

10. The method according to claim 7, wherein steps a) and e) form a
battery having a battery voltage capacity and wherein steps b) and f)
from a capacitor having a capacitor voltage capacity at least as great as
the battery voltage capacity.

11. The method according to claim 7, wherein steps a) and e) form an
integrated energy storage unit having a battery internal resistance and
wherein steps b) and f) from a capacitor having a capacitor internal
resistance nor more than one half that of the battery internal
resistance.

12. The method according to claim 7, wherein steps c) and d) are
performed after steps e) and f).

13. The method according to claim 7, wherein step g) is the last step
performed in the method.

14. An integrated energy storage unit manufactured by a process
comprising the steps of: a) inserting positive battery plates and
negative battery plates into a battery pouch; b) inserting positive
capacitor plates and negative capacitor plates into a capacitor pouch; c)
electrically coupling the positive battery plates and the positive
capacitor plates to each other; d) electrically coupling the negative
battery plates and the negative capacitor plates to each other; e) adding
a battery electrolyte to the battery pouch; f) adding a capacitor
electrolyte to the capacitor pouch; and g) simultaneously charging the
battery and the capacitor from a charge source.

15. The integrated energy storage unit according to claim 14, wherein
step g) is the last step performed in the method.

16. The integrated energy storage unit according to claim 14, steps a)
and e) form a battery and steps b) and f) form a capacitor having a
capacitor voltage capability at least as great as the battery voltage
capability.

17. The integrated energy storage unit according to claim 14, wherein
steps a) and e) form a integrated energy storage unit having a battery
internal resistance and wherein steps b) and f) from a capacitor having a
capacitor internal resistance not more than one half that of battery
internal resistance.

18. An integrated power unit comprised of a plurality of the integrated
energy storage units according to claim 14 electrically coupled to each
other in series.

19. An integrated power unit comprised of a plurality of the integrated
energy storage units according to claim 14 electrically coupled to each
other in parallel.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] U.S. patent application Ser. No. 12/699,110, filed on Feb. 3, 2010
is incorporated herein by reference in its entirety.

FIELD OF INVENTION

[0002] The present invention relates to an energy storage unit that
integrates a lithium ion battery and a capacitor.

BACKGROUND

[0003] Capacitors may be used in combination with batteries to support
high power demands, such as, for example, in hybrid or electric vehicles,
which require a large amount of power for quick acceleration. A battery
alone, which is slow to respond due to the slow mobility of ions within
the battery, cannot provide the quick release of power required to meet
the demands of acceleration. Capacitors have been electrically coupled to
batteries to provide power from the battery to charge the capacitor so
that the capacitor can provide the quick release of power required for
acceleration.

[0004] It would be beneficial to provide a single unit that provides
increased electrical performance over existing current battery/capacitor
assemblies.

SUMMARY OF THE PRESENT INVENTION

[0005] Briefly, the present invention provides an integrated energy
storage unit comprising a container and a battery housed within the
container. The battery comprises a positive battery terminal, a negative
battery terminal, and a battery electrolyte. A capacitor is housed within
the container, separate from the battery. The capacitor comprises a
positive capacitor terminal, a negative capacitor terminal, and a
capacitor electrolyte. A plurality of connectors electrically couples the
battery and the capacitor to each other in parallel. A positive lead is
electrically coupled to the positive battery terminal and the positive
capacitor terminal. The positive lead extends from the container. A
negative lead is electrically coupled to the negative battery terminal
and the negative capacitor terminal. The negative lead extends from the
container.

[0006] The present invention also provides an integrated energy storage
unit comprising a container and a battery assembly comprising a plurality
of batteries housed within the container. The plurality of batteries is
electrically coupled together in parallel or series. A capacitor assembly
comprises a plurality of capacitors housed within the container, separate
from the plurality of batteries. The plurality of capacitors is
electrically coupled together in series. The battery assembly and the
capacitor assembly are electrically coupled to each other in parallel.

[0007] Further, the present invention provides an integrated energy
storage unit comprising a plurality of batteries electrically coupled
together in parallel. Each of the plurality of batteries is housed in its
own battery pouch. A plurality of capacitors is electrically coupled
together in series. Each of the plurality of capacitors is housed in its
own capacitor pouch. The plurality of batteries is electrically coupled
to the plurality of capacitors in parallel.

[0008] The present invention also provides a method of assembling an
integrated energy storage unit comprising the steps of manufacturing a
battery having a positive battery terminal and a negative battery
terminal; manufacturing a capacitor separate from the battery, the
capacitor having a positive capacitor terminal and a negative capacitor
terminal; electrically coupling the positive battery terminal and the
positive capacitor terminal to each other; electrically coupling the
negative battery terminal and the negative capacitor terminal to each
other; and simultaneously charging the battery and the capacitor from a
charge source.

[0009] The present invention further comprises a method of assembling an
integrated energy storage unit comprising the steps of inserting positive
battery plates and negative battery plates into a battery pouch;
inserting positive capacitor plates and negative capacitor plates into a
capacitor pouch; electrically coupling the positive battery plates and
the positive capacitor plates to each other; electrically coupling the
negative battery plates and the negative capacitor plates to each other;
adding a battery electrolyte to the battery pouch; adding a capacitor
electrolyte to the capacitor pouch; and simultaneously forming the
battery and the capacitor from a charge source.

[0011] The foregoing summary, as well as the following detailed
description of the invention, will be better understood when read in
conjunction with the appended drawings. For the purpose of illustrating
the invention, there is shown in the drawings certain embodiments of the
present invention. It should be understood, however, that the invention
is not limited to the precise arrangements and instrumentalities shown.

[0012] In the drawings:

[0013]FIG. 1 is an exploded perspective view of a battery employing a
plurality of integrated energy storage unit according to a first
exemplary embodiment of the present invention;

[0014]FIG. 2 is an electrical schematic drawing of the integrated energy
storage unit according to the first exemplary embodiment of the present
invention;

[0015]FIG. 3 is a flowchart illustrating an exemplary method of
manufacturing an integrated energy storage unit according to an exemplary
embodiment of the present invention;

[0016]FIG. 4 is an electrical schematic drawing of a plurality of
Integrated energy storage units electrically coupled to each other in
series according to an exemplary embodiment of the present invention; and

[0017]FIG. 5 is an electrical schematic drawing of a plurality of
integrated energy storage units electrically coupled to each other in
parallel according to an exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0018] In describing the embodiments of the invention illustrated in the
drawings, specific terminology will be used for the sake of clarity.
However, the invention is not intended to be limited to the specific
terms so selected, it being understood that each specific term includes
all technical equivalents operating in similar manner to accomplish
similar purpose. As used herein, devices are "electrically coupled" to
each other when a path is provided for a transfer of electrons between
the devices. Also, a "battery" may be comprised of a single cell or
multiple cells. It is understood that the drawings are not drawn to
scale.

[0019] The following describes particular examples of embodiments of the
present invention. It should be understood, however, that the invention
is not limited to the embodiments detailed herein. Generally, the
following disclosure refers to an integrated energy storage unit and a
method of manufacturing and energizing the unit.

[0020] The inventive integrated energy storage unit includes at least one
capacitor coupled in parallel to at least one battery to form a hybrid
cell. In an exemplary embodiment, the battery is a rechargeable
lithium-ion battery, although those skilled in the art will recognize
that other types of batteries, such as, for example, a lead acid or NiMH
battery, may be used within the scope of the present invention. The
inventive integrated energy storage unit may be used in applications
ranging from Hybrid Electric Vehicles (HEV), Plug-in Hybrid Electric
Vehicles (PHEV), and Electric Vehicles (EV). The inventive integrated
energy storage unit may also be used as an energy storage system for
various applications, such as, for example, Uninterrupted Power Supply
(UPS), telecommunications, and power regulation. Further, the inventive
integrated energy storage unit may be used wherever power may be
instantaneously required. Additionally, the inventive integrated energy
storage unit may be considered as an extended energy storage unit, as it
provides extended energy tor operating, among other things, the
above-referenced devices.

[0021] Referring to FIGS. 1 and 2, a first exemplary embodiment of an
integrated energy storage unit 100 includes a container 110 that retains
a battery 120 housed within container 110, as well as a capacitor 130
housed within container 110, separate from battery 10. Container 110 may
be a large format prismatic case that, is well known to those skilled in
the art.

[0022] An integrated cell electrical bus 112 is inserted over the top of
container 110 to seal battery 120 and capacitor 130 within integrated
energy storage unit 100 and to provide electrical contacts for an
integrated battery electrical bus 114. As illustrated in FIG. 1, a
plurality of integrated energy storage units 100 may be coupled together
and housed inside a battery case 116 to form an integrated power unit
101. Integrated battery electrical bus 114 electrically couples all of
integrated energy storage units 100 together and provides a single
positive electrode 117 and a single negative electrode 118 for coupling
to a charge source 50 (illustrated schematically in FIG. 2) or a device
(not shown) to be powered by integrated power unit 101. Battery case 116
may also include a battery management space 119 to house a battery
management system (not shown). The battery management system may include
at least one controller electrically coupled to each of the plurality of
integrated energy storage units 100 to manage the charging and
discharging of the plurality of integrated energy storage units 100. A
battery cover 121 is inserted over the top of battery case 116 to seal
the plurality of integrated energy storage units 100 and the battery
management system within battery case 116.

[0023] Compared to connecting a battery housed in one container to a
capacitor housed in a second container, the present invention provides
economic advantages of relatively lower cost of manufacture, lower
packaging cost, better utilization of physical space, improved energy
density, and better performance.

[0024] The present invention also provides energy management performance
advantages of lower inductance, lower resistance, lower power dissipation
from physically shorter, wider internal conductive paths and
interconnections within and between battery(s) 120 and capacitor(s) 130
due to integration. The relative lower inductance and lower resistance of
the present invention provides performance advantages of greater
stability in energy level, faster response time, and greater efficiency
in storing and delivering energy than prior art devices.

[0025] A benefit of the integration of battery 120 with capacitor 130 is
related to the reduction in the length of electrical bus connection 112,
relative to prior art connections. For example, prior art
battery-to-capacitor electrical bus connections for quick release of
power in the 100 amp to 150 amp range typically use copper or aluminum
rectangular straps or bars that are several inches long, about an inch
(2.54 cm) wide, and about 1/8 inch (0.32 cm) thick. Such a strap or bar
typically results in at least 30 micro ohms of resistance and at least 30
micro henries of inductance, not including contact resistance. The
inventive device, having electrical bus connection 112 length of a half
to a third the length of prior art straps or bars, reduces the
battery-to-capacitor connection resistance and inductance by a half to a
third, down to between about 10 to about 15 micro ohms, and between about
10 and about 15 micro henries.

[0026] Battery 120 includes a plurality of positive plates 122 and a
plurality of negative plates 124 (only one positive plate 122 and one
negative plate 124 are shown for clarity) stored within a battery pouch
152. A positive battery terminal 126 is electrically coupled to the
plurality of positive plates 122 and a negative battery terminal 127 is
electrically coupled to the plurality of negative plates 124. While a
single positive battery terminal 126 and a single negative battery
terminal 127 are illustrated, those skilled In the art will recognize
that battery 120 may include more than one positive battery terminal 126
and/or more than one negative battery terminal 127. A battery electrolyte
128 is in contact with positive plates 122 and negative plates 124 and is
used to transport ions between positive plates 122 and negative plates
124. Battery 120 may be a rechargeable lithium-ion battery.

[0027] Capacitor 130 includes a positive plate 132 and a negative plate
134 stored within a capacitor pouch 154. A positive capacitor terminal
136 is electrically coupled to positive plate 132 and a negative battery
terminal 137 is electrically coupled to negative plate 134. While a
single positive capacitor terminal 136 and a single negative capacitor
terminal 137 are illustrated, those skilled in the art will recognize
that capacitor 130 may include more than one negative capacitor terminal
137. A capacitor electrolyte 138 is in contact with positive electrode
132 and negative electrode 134 and is used to transport electrons between
positive electrode 132 and negative electrode 134. Capacitor electrolyte
138 may be an aqueous or a non-aqueous electrolyte.

[0028] Capacitor 130 may be an electrochemical double layer capacitor or a
super capacitor, which are both well known in the art. Capacitor 130 may
be manufactured in a roll-to-roll or other known coating manufacturing
process. Carbon nanofoam powders, such as those provided by Ocellus, Inc.
of Livermore, Calif., may be used in the manufacture of plates 132, 134
in capacitor 130. The surface area of the nanofoam powder ranges between
about 2000 m2/g and about 2400 m2/g.

[0029] In an exemplary embodiment, the coating may be formed by making a
slurry with the nanofoam powder, a solvent, and a binder. The solvent may
be water or other suitable solvent, and the binder makes up less than 10%
by weight, and more preferably, less than 5% by weight of the coating.
The binder does not occlude the porosity in the nanofoam. The binder is
comprised of water soluble polymers including carboxymethylcellulose,
(CMC), poly vinyl alcohol, polyvinylpyrrolidone, poly acrylic acid,
polymethacrylic acid, polyethylene oxide, polyacrylamide,
poly-N-isopropylearylamide, Poly-N,N-dimethylacrylamide,
polyethyleneimine, polyoxyethylene, polyvinylsulfonic acid,
poly(2-methoxyethoxyethoxyethylene), stymie butadiene rubber (SBR),
Butadiene-acrylonitrile, rubber (NBR) Hydrogenated NBR (HNBR),
epichlorhydrin rubber (CHR), polytetrafluroethylene (PTFE), EPDM, and
acrylate rubber (ACM). The water soluble thickener may be selected from
the group consisting of natural cellulose, physically and/or chemically
modified cellulose, natural polysaccharides, chemically and/or physically
modified polysaccharides, carboxymethyl cellulose, hydroxy methyl
cellulose and methyl ethyl hydroxy cellulose. The binder is also
comprised of polymers soluble in organic solvents such as PVDF and its
copolymers.

[0030] Connectors 140, 142 electrically couple battery 120 and capacitor
130 in parallel, forming integrated energy storage unit 100. Connector
140 may be electrically coupled to positive battery terminal 126 and
positive capacitor terminal 136. Connector 140 may be electrically
coupled to a positive lead 144, which extends outwardly from container
110. Connector 142 may he electrically coupled to negative battery
terminal 127 and negative capacitor terminal 137. Connector 142 may be
electrically coupled to a negative lead 146, which extends outwardly from
container 110. A device (not shown) that is to be powered by integrated
energy storage unit 100 may be electrically coupled to positive lead 144
and negative lead 146.

[0031] Integrated energy storage unit 100 according to the present
invention allows for modularity in assembling integrated energy storage
unit 100. For example, battery 120 may be a 3.2 volt battery and
capacitor 130 may be a 1000 Farad capacitor. More specifically, a lithium
iron phosphate battery may have a voltage between about 2.5 volts and
about 3.6 volts, while a lithium nickel cobalt manganese battery may have
a voltage between about 3 volts, and about 4.2 volts. The inventive
integrated energy storage unit 100 provides large independent
capacitance, with the same characteristics of a super capacitor.

[0032] In an exemplary embodiment, it may be desired to provide integrated
energy storage unit 100 having 460 volts and 100 Farad. In this
embodiment, integrated energy storage unit 100 may include 144 batteries
120 and 144 capacitors 130.

[0033] Regardless of the number of batteries 120 and the number of
capacitors 130 that comprise integrated power unit 101, it is desired
that the capacitor internal resistance is not more than one half that of
the battery internal resistance. In small duration high power pulses,
battery 120 does not initially participate (i.e. charge state initially
does not charge) due to slow ion mobility and high internal resistance
compared to the much faster electron mobility and lower internal
resistance of capacitor 130. Further, it is desired that the voltage
limit of capacitor 130 is greater than the voltage of battery 120.

[0034] In an exemplary embodiment of a method of manufacturing integrated
energy storage unit 100, illustrated in the flowchart 400 of FIG. 3, in
step 402, battery 120 may be manufactured by inserting the plurality of
positive plates 122 with positive battery terminal 126 and the plurality
of negative plates 124 with negative battery terminal 127 into battery
pouch 152. In step 404, capacitor 130 may be manufactured concurrently
but separately from battery 120 by inserting the plurality of positive
plates 132 with positive capacitor terminal 136 and the plurality of
negative plates 134 with negative capacitor terminal 137 into capacitor
pouch 134.

[0037] Integrated energy storage unit 100 provides a more complete and
stable formation of a lithium battery than if a lithium battery were
formed alone. In an experiment, six unformed 40 Ampere hour (Ah) lithium
iron phosphate (LFP40) test cells (see Table I below) were each
electrically coupled to separate uncharged capacitors and formed
according to the present invention, and six other cells out of the same
lot were formed alone as control ceils (see Table 1.1 below). After
formation, the capacitors were removed from the six test cells for C/3 (3
hour) discharge tests. The C/3 discharge test data results show that the
six test cells formed with a capacitor out-performed the six control
cells that were formed alone.

[0038] For the control cells, their first cycle average capacity was 96.5%
of their fifth cycle capacity, while for the test cells, their first
cycle average capacity was 98.4% of their fifth cycle capacity, which
showed a 1.9% improvement Both test and control cells on average achieved
the same capacity by the fifth cycle; both above their 40 Ah rating by
about 1.17 Ah or by 2.9%. All test cells, however, achieved rated
capacity in the first cycle, while the control cells took until the third
cycle for all to achieve rated capacity. Also the test ceils showed less
variation (1.00 percent) from average capacity than control cells (2.32
percent).

[0039] The test cells also had a lower average impedance and slightly less
variation at the 5th cycle compared to the control cells. Tables III
and IV below show that the 5th cycle impedance average for the test cells
(Table III) was 1.5813 mOhm compared to 1.6843 mOhm for the controls
cells (Table IV), which is 0.103 mOhm (6.1%) lower.

[0040] As shown in FIG. 4, a plurality of integrated energy storage units
100, 100a, 100b may be coupled together in series, forming a power unit
500. Each integrated energy storage unit, 100, 100a, 100b may be charged
separately prior to electrically coupling power unit 500 to other devices
(not shown), such as, for example, an electric or hybrid vehicle motor.

[0041] Alternatively, as shown in FIG. 5, a plurality of integrated energy
storage units 100, 100a, 100b may be coupled together in parallel,
forming a power unit 600. Each integrated energy storage unit 100, 100a,
100b may be charged separately prior to electrically coupling power unit
600 to other devices (not shown), such as, for example, an electric or
hybrid vehicle motor. The coupling of integrated energy storage units
100, 100a, 100b in series, parallel, or even a combination of series and
parallel is performed to provide a desired voltage or current, depending
on the intended use of the device.

[0042] With battery 120 and capacitor 130 electrically coupled together to
form integrated energy storage unit 100, battery 120 and capacitor 130
may be controlled together by a battery management system (not shown).
Prior art assemblies using capacitors and batteries as individual strings
require different balancing systems, one for the capacitors and one for
the batteries. With the hybrid system according to the present invention,
a single balancing system manages both.

[0043] Some advantages of using integrated energy storage units 100, 200
300, and 500 include increasing the initial charge and discharge capacity
and achieving the rated capacity m the first charge cycle, which results
in reduced cycling time which lowers manufacturing cost.

[0044] While the principles of the invention have been described above in
connection with preferred embodiments, it is to be clearly understood
that this description is made only by way of example and not as a
limitation of the scope of the invention.